package BinaryTree;
/*
* 合并二叉树
* 二叉树前序遍历的应用,先合并根节点再合并左右子树
* */
public class MergeTrees617 {
    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
        if(root1==null){
            return root2;
        }
        if(root2==null){
            return root1;
        }
        TreeNode node = new TreeNode(root1.val + root2.val);
        node.left=mergeTrees(root1.left,root2.left);
        node.right=mergeTrees(root1.right,root2.right);
        return node;

    }
}
